ACL Mechanical Property Changes in Female Collegiate Basketball Players During a Competitive Season

[Introduction and Rationale] The anterior cruciate ligament (ACL) is a critical stabilizer of the knee joint, particularly during high-demand athletic activities involving pivoting, rapid deceleration, and landing. Female athletes exhibit a significantly higher incidence (2 to 9 times) of non-contact ACL injuries compared to their male counterparts. While acute trauma is a well-recognized mechanism, emerging evidence suggests that cumulative loading over a competitive season may lead to subclinical alterations in the ligament's mechanical properties. These changes, such as decreased stiffness, may predispose athletes to injury by compromising joint stability and neuromuscular control. However, objective in vivo data regarding the seasonal adaptation of the ACL in elite athletes remains sparse.

[Study Design and Participants] This prospective cohort study will recruit 60 elite female collegiate basketball players from Division I teams of the University Basketball Association (UBA). The research is designed to track longitudinal changes in ACL integrity and functional performance across a full competitive season.

[Study Procedures]

Participants will undergo standardized assessments at two distinct time points:

Pre-season Assessment (Baseline): Conducted in October, prior to the start of the competitive UBL season.

Post-season Assessment: Conducted in April, following the conclusion of the competitive basketball season.

During each session, two primary modalities will be employed:

1. Imaging-based Assessment (Shear Wave Elastography):

   Shear Wave Elastography (SWE) will be utilized to non-invasively quantify the mechanical properties of the ACL. The assessment will focus on:

   Shear Wave Speed (m/s) Shear Modulus (kPa) These metrics serve as direct indicators of tissue stiffness and structural integrity. Measurements will be taken with the knee in a consistent, standardized position to ensure reproducibility.

2. Functional Biomechanical Performance (Countermovement Jump):

Participants will perform Countermovement Jumps (CMJ) on KFORCE force plates to evaluate lower limb dynamic performance. This functional test provides insight into the athlete's neuromuscular status. Key variables collected will include:

Jump Height (cm) Reactive Strength Index (RSI): Calculated as the ratio of jump height to ground contact time.

Force Metrics: Including eccentric and concentric impulse to analyze force production and absorption strategies.

[Research Goal] By integrating imaging-based mechanical data with functional biomechanical outcomes, this study seeks to identify potential "fatigue" markers or adaptive responses in the ACL resulting from seasonal athletic demands. The findings aim to bridge the gap between clinical imaging and athletic performance, ultimately informing individualized injury prevention strategies and early detection protocols for female athletes at risk.